Do Pleistocene rock paintings depict Sulawesi warty pigs (Sus celebensis) with a domestication character

The Indonesian island of Sulawesi harbours numerous early rock paintings of the endemic Sulawesi warty pig (Sus celebensis). Several S. celebensis images, including one dated to at least 45,500 years ago (ka), portray these suids with an anatomical character not observed in the living species: a pair of teat-like protuberances in the neck area. This feature seems to be most consistent morphologically with neck “wattles”, cutaneous appendages only manifested in modern domestic swine (Sus scrofa) and some other domesticated ungulates (e.g. goats). The notion that the trait portrayed by the Late Pleistocene artists is a domestication character is clearly contentious. We therefore consider: (1) whether we have misidentified the trait – a common problem in rock art analysis; (2) whether wattles are a genuine domestication trait; and (3) if so, whether the notion that Pleistocene people domesticated S. celebensis is plausible. A clear resolution to all of these problems evades us; however, our investigation of this anomaly in the ancient rock art poses important questions about the nature and complexity of early human–pig relations in this island.